Hach Dissolved Oxygen Meter Use Precautions and Electrode Maintenance
1. Precautions for using the Hach dissolved oxygen meter
1) Connect the stabilized power supply and battery before using the instrument.
2) When the newly purchased instrument is not used for a long time, the electrode should be filled with electrolyte (otherwise the dissolved oxygen value cannot be measured).
3) Pull the electrode sheath back, plug in the oxygen electrode, make sure that the plug is in good contact with the socket (a click is heard), and conduct polarization for 5 minutes.
4) Zero oxygen calibration: put the electrode into 5% sodium sulfite solution, the closer the displayed value is to zero, the better. Full-scale calibration in air: The displayed value corresponds to the saturated dissolved oxygen value at the current temperature. If the difference is large, repeat zero oxygen calibration and full scale calibration twice.
5) The instrument should be calibrated regularly and the electrolyte and membrane should be replaced to ensure measurement accuracy. If the instrument is used frequently, it is recommended to calibrate once every 10 days. When installing the film, make sure that the film is in full contact with the gold surface, otherwise there will be zero oxygen, or the value will be inaccurate or unstable during the measurement process.
6) The dissolved oxygen electrode is used for a long time, especially after measuring sewage, the silver electrode in the electrode will be blackened and oxidized. At this time, the electrolyte and film should be replaced frequently, and the surface of the silver electrode and the gold surface should be cleaned. If the indicators are not ideal, you should consider buying a new electrode.
7) The dissolved oxygen electrode can be stored in distilled water when not in use. The battery should be taken out when the instrument is not used for a long time.
8) When sampling and measuring, the electrode and the solution should move relative to each other and not stand still (stir slowly).
Second, the use and maintenance of the electrode of the Hach dissolved oxygen meter
1) The electrodes of the dissolved oxygen meter should be cleaned once every 1 to 2 weeks. If there are pollutants on the diaphragm, it will cause measurement errors. Care should be taken when cleaning, taking care not to damage the diaphragm. Rinse the electrode of the dissolved oxygen meter in clean water. If the dirt cannot be washed off, carefully scrub it with a soft cloth or cotton cloth.
2) The zero point and range of the electrode of the dissolved oxygen meter should be re-calibrated in 2~3 months.
3) The electrode of the dissolved oxygen meter should be regenerated about once a year. When the measurement range cannot be adjusted, the dissolved oxygen electrode needs to be regenerated. Electrode regeneration includes replacing the internal electrolyte, replacing the diaphragm, and cleaning the silver electrode. If the silver electrode is observed to be oxidized, it can be polished with fine sandpaper.
4) If the electrode of the dissolved oxygen meter leaks during use, the electrolyte must be replaced.
